1. Field of the Invention
The present invention relates to a stepping motor valve for a refrigerator, and more particularly, to a stopper structure of a stepping motor constituting a stepping motor valve.
2. Description of the Related Art
Generally, refrigerating apparatuses, such as refrigerators, air conditioners and kimchi refrigerators, control temperature therein by using refrigerants of high temperature and pressure that circulate in refrigerating cycles. Among the refrigerating apparatuses, a refrigerator will be described herein by way of example.
FIG. 1 shows a refrigerating cycle of a conventional refrigerator.
As shown in the figure, the refrigerating cycle comprises a compressor 11 for compressing a refrigerant, a condenser 13 for radiating heat contained in the refrigerant compressed by the compressor 11, and a dryer 15 installed at a rear end of the condenser 13 to remove moisture remaining in the refrigerant.
Further, refrigerant lines are provided between an outlet of the dryer 15 and inlets of a plurality of expansion valves 21 and 23 connected to the outlet. A three-way stepping motor valve 17 is also installed to connect a refrigerant line 19c on the side of the outlet of the dryer 15 to refrigerant lines 19a and 19b on the sides of the inlets of the expansion valves 21 and 23.
The stepping motor valve 17 is constructed to selectively open or close the refrigerant lines 19a and 19b connected to the expansion valves 21 and 23 under control of a microcomputer (not shown). That is, with the stepping motor valve 17, it is possible to open or close the refrigerant line 19a connected to the expansion valve 21, the refrigerant line 19b connected to the expansion valve 23, or both the refrigerant lines 19a and 19b, by selectively opening or closing the refrigerant lines 19a and 19b connected to the expansion valves 21 and 23, respectively, with respect to the inlets thereof connected to the dryer 15.
Evaporators 25 and 27 are connected to rear ends of the expansion devices 21 and 23, respectively. The evaporators 25 and 27 generate cold air for cooling foodstuffs stored in the refrigerator. Refrigerant lines connected to the rear ends of the evaporators 25 and 27 are connected to the compressor 11, so that the refrigerating cycle, which is composed of compressor 11→condenser 13→dryer 15→stepping motor valve 17→expansion devices 21 and 23→evaporators 25 and 27→compressor 11, is formed.
Therefore, in the case where there are the plurality of evaporators 25 and 27, it is possible to control supply of cold air according to the storage space of the refrigerator. That is, according to the operation for opening the stepping motor valve 17, it is possible to construct a refrigerating cycle composed of compressor 11→condenser 13→dryer 15→stepping motor valve 17→expansion device 21→evaporator 25→compressor 11, a refrigerating cycle composed of compressor 11→condenser 13→dryer 15→stepping motor valve 17→expansion device 23→evaporator 27→compressor 11, or a refrigerating cycle composed of compressor 11→condenser 13→dryer 15→stepping motor valve 17→expansion devices 21 and 23→evaporators 25 and 27→compressor 11.
In other words, the refrigerant line 19a connected to the stepping motor valve 17, the expansion valve 21 and the evaporator 25 are components for controlling cold air in a first storage space. The refrigerant line 19b connected to the stepping motor valve 17, the expansion valve 23 and the evaporator 27 are described as components for controlling cold air in a second storage space.
Meanwhile, FIG. 2 shows the structure of the stepping motor valve shown in FIG. 1, and FIG. 3 shows a cross section taken along line A-A′ of FIG. 2.
As shown in these figures, the three-way stepping motor valve 17 has a stepping motor 30 comprising a stator 31 and a rotator 33. A portion of a rim of a bottom surface of the rotator 33 protrudes downward to form a catching part 34, and a valve body 35 is provided at a central portion of the bottom surface of the rotator 33.
An opening area 36 is formed at a portion of a bottom surface of the valve body and a closing area 37 is formed at the remaining portion thereof. The opening area 36 functions to open first and second output ports 47 and 49 to be described later, and the closing area 37 functions to close the first and second output ports 47 and 49.
Further, a valve housing 39 is provided below the stepping motor 30, and a port support 41 is installed within the valve housing 39. A top surface of the port support 41 is provided with a protrusion 43 of which a top surface comes into close contact with the bottom surface of the valve body 35, and an input port 45 is provided to penetrate the top surface of the port support 41. The first and second output ports 47 and 49 are provided to penetrate a portion of the top surface of the protrusion 43.
The input port 45 functions to supply the refrigerant into the valve housing 39, and the first and second output ports 47 and 49 function to discharge the refrigerant that has been supplied through the input port 45 into the valve housing 39. At this time, for example, the first and second output ports 47 and 49 can communicate with the refrigerant lines 19a and 19b shown in FIG. 1, respectively.
Meanwhile, a stopper 51 is formed at a portion of the top surface of the port support 41, which corresponds to the outside of the protrusion 43. The stopper 51 is made of a rubber material and functions to cause the microcomputer to sense the position of the rotator 33 at an initial control stage. That is, if a refrigerator is first operated after coming onto the market, the stepping motor valve 30 is controlled with respect to a position where one side of the catching part 34 comes into contact with one side of the stopper 51 as the rotator 33 rotates in one direction.
Reference numeral A1 that has not yet been described is a rotation axis about which the rotator 31 rotates.
However, the conventional stepping motor valve constructed as above has the following problem.
As described above, the stopper 51 is made of the rubber material, and the catching part 34 that comes into contact with the stopper 51 for the purpose of the initial control of the stepping motor valve 30 is formed integrally with the rotator 33 made of a relatively rigid material such as a magnet. Thus, if the catching part 34 collides against the stopper 51 many times due to frequent initial control operations of the stepping motor 30 or deviations in its operation, the stopper 51 may be worn, resulting in malfunction of the stepping motor 30.